A data center is a facility that houses computer systems and various networking, storage, and other related components. Data centers may, for example, provide computing services to businesses and individuals as a remote computing service or to provide “software as a service” (e.g., cloud computing). The computing resources provided by a data center may include various types of resources, such as data processing resources, data storage resources, data communication resources, and the like.
To facilitate increased utilization of data center resources, virtualization technologies may allow a single physical computing machine to host one or more instances of virtual machines that appear and operate as independent computer machines to a connected computer user. With virtualization, the single physical computing device can create, maintain, or delete virtual machines in a dynamic manner. When a customer of a data center requests a new virtual machine instance, the data center may provide a virtual machine management service that identifies a “slot” for executing the new instance. Customers may sometimes request a virtual machine instance with a particular configuration. In some cases, the configuration may include software and data that is provided by the customer or by a third party supplier.